shower problem, combi boiler - please help!

anne · 20 Jan 2004

Hello,
We've inherited an olde style one lever thermostatic shower in our house which has a knightsbridge 24kw combi boiler.

Our shower does not get very warm, and you only get hot water out of the taps at a low flow rate.

We were told by a boiler man that our boiler isn't up to the job and to get a hot shower, we need to block off the cold or buy a new boiler.

We have blocked off the cold by fitting a valve and reduced the hot flow, so our shower is hot now, but the temperature isn't adjustable.

We're wondering - would fitting a new shower unit help at all? Is a thermostatic one the best one to use in this situation? If so, which is the best? What we really need is something that will allow us to increase cold flow to control the temperature.

Or should we give up and just fit an electric shower?

Thanks all for your help.

Anne

oilman · 20 Jan 2004

Electric showers go up to about 10kW, and you can get good showers with them. Your boiler has an effective 15kW to 20kW output into the heat exchanger, so you should get a reasonable shower from that. Some boilers have a mixer valve you can adjust to set the output temperature, does yours?

How old is the boiler? Do you have a water conditioner fitted?
If the boiler is 2 years old and you live in a hard water area and you dont have a conditioner fitted, you probably have a scaled up heat exchanger.

If you have a magnetic or electronic conditioner, well I could get sued for making a comment. However, if you look here , they make something that works. So once your heatexchanger is descaled, fit one of these and the problem should bbe fixed.

anne · 20 Jan 2004

Hello,

The boiler is about 5 years old I think but I think our water is fairly soft- we don't get furry kettles or scummy tea. We're on the wirral.

We have had someone to look at the boiler but he said it was working fine. He didn't service it, however. We're not sure it heats water up as it should.

Don't know about a mixer valve.

anne

oilman · 20 Jan 2004

That was quick, as you may have soft water, scaling might not happen.
Is the flow from the hot tap about the same as the flow from the cold tap?

What is the flow rate in litres/minute? You can use a bucket in the sink to find this out. (Usually a problem if you have low water pressure)

aj70 · 20 Jan 2004

We had the exact same problem with our combi boiler when we moved into our new house.

It turned out to be the valve which switched it from central heating to hot water. It wasn't working properly and needed replacing. It cost us £220 + vat to be fixed (a very quick job), but we were so happy to have a hot shower, we soon forgot the cost. I hope this helps.

oilman · 20 Jan 2004

It cost us £220 + vat to be fixed

Wow! thanks! my prices have just doubled (and then some). I'm going to be rich

breezer · 20 Jan 2004

me too and i am not even a plumber, i will fit these

only cost 34.66 each

oilman · 20 Jan 2004

me too and i am not even a plumber,....

Nor am I.

What make are they? I spend so much time on the forum I don't get out much, and I've not seen one like that.

anne · 21 Jan 2004

aj70, what sort and power is your boiler?

Oilman - hotwater flow rate is 10l/min, hot and cold pressures approx equal.

At 10l/min, water temp is raised from 8 degC to 34 degC

At 3l/min, water temp is raised from 8 degC to 49 degC

Thanks for your help!

anne

oilman · 21 Jan 2004

At 10l/min you should probably get a 35 deg C rise, which means the temp should go up to 43. However it seems that your temperatures from the tap are not too bad. It is a problem with combies that they have a limited hot water supply, fine for washing up, but baths? No. Showers? Possibly.

Can you control the temperature with your shower control? You may need to replace this part to get the shower to work properly.

aj70 · 21 Jan 2004

In answer to your question I have a Vaillant 824E.

I dug out my receipt and it was actually £220 inc vat. There is no break up of parts and labour but the details state "trace fault on Vaillant to diverter valve. Supply and fit new valve.

Oilman - what would you have charged me for that?

oilman · 21 Jan 2004

It would depend on whether the valve was the problem or just the head, which is more often the case. It also depends on where you are. If you're within say 20 miles of where I live, you would probably get your boiler serviced as well for what you paid. But I don't do gas

. If you live a long way away, it would cost you more.

breezer · 21 Jan 2004

obvious q, where are you?

I was thinking (silly i know) how about .......no its too silly?

oilman · 21 Jan 2004

obvious q, where are you?

You should know better,

that sort of information compromises anonimity. Yes, I know, several people give bits of info like that away from time to time, but I don't particularly want any fame (or infamity) so I will continue to dress in a noddy suit and ear muffs for work and drive a green pickup.

Anyway, to answer your question, I'm sitting in a chair.

diynot

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shower problem, combi boiler - please help!

breezer

breezer

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